This invention relates to a control means which prevents overspeed of a motor used on a pneumatic tool.
Hand-held pneumatic tools, which operate at high rotary speed, i.e., up to 12,000 r.p.m., such as on tools used in grinding operations, generally incorporate governors designed to maintain a predetermined operative speed. An example of such a governor can be found in U.S. Pat. No. 3,552,410 issued Jan. 5, 1971, to Lester A. Amtsberg.
To avoid dangerous overspeeds, which could happen if the governor failed to properly function, an overspeed control means is often utilized to tools of the type under consideration. Examples of such overspeed safety devices can be found in U.S. Pat. No. 3,923,429 issued Dec. 2, 1975 to Raymond J. Schaedler and Robert D. Roth, as well as U.S. Pat. No. 3,749,530 issued July 31, 1973 to German Amador.
The overspeed control means of the subject invention represents an improvement over such devices of the prior art primarily because of its extreme simplicity of structure providing low manufacturing costs and easy maintenance, while affording reliable, durable service.